Lens barrel cam mechanism and method of manufacturing rotary member for use with cam mechanism

ABSTRACT

A lens barrel cam mechanism having a linearly movable member for holding an optical element and which includes a cam follower and a rotary member rotatable relative to the linearly movable member and which has a cam groove with which the cam follower is slidably engaged formed on its circumferential surface, wherein the rotary member is rotated to guide the cam follower so that the linearly movable member is moved forward and backward in the optical axis direction includes a gear portion, the gear portion being developed at the outside of a radius direction and having teeth on its outer periphery and a cam groove opening portion, wherein the cam groove opening portion and the gear portion are provided such that they become substantially coincident with each other on the same vertical plane vertical to the optical axis direction.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese PatentApplication JP 2005-306464 filed in the Japanese Patent Office on Oct.20, 2005, the entire contents of which being incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lens barrel cam mechanism capable ofextending and retracting a lens barrel by a cam mechanism and a methodof manufacturing a rotary member suitable for use with such cammechanism.

2. Description of the Related Art

Cited Patent Reference 1, for example, has hitherto described this kindof lens barrel cam mechanism. That is, the Cited Patent Reference 1described technologies relating to a light amount adjusting apparatuslocated in a light path of an optical system and a camera incorporatingtherein a light amount adjusting apparatus (hereinafter referred to a“first related-art example”. A camera according to this firstrelated-art example includes an optical system having a first lens groupof which light exit surface is formed as a concave surface and a secondlens group including a convex surface on which light from the first lensgroup becomes incident and which can be magnified with its optical irisposition between the first lens group and the second lens group. Thereare also included a filter apparatus having predetermined transmittancelocated behind the second lens group and which can be moved between theposition to open an exposure opening and the position to shut theexposure opening and a control unit for controlling based on themagnified states of the optical system and shutter speeds whether thefilter apparatus is to be moved to the position to shut the exposureopening. This camera according to the first related-art example ischaracterized in that, if the shutter speed becomes higher than apredetermined value in the state in which the filter apparatus islocated at the position to open the exposure opening, then the filterapparatus is moved to the position to shut the exposure opening so thatthe camera becomes able to take a picture at a lower shutter speed.

According to the camera having the above-mentioned arrangement describedin the Cited Patent Reference 1, there can be achieved effects in whichthe arrangement of a shutter diaphragm can be optimized, the occurrenceof a shutter light amount difference of the shutter diaphragm can bedecreased, more suitable exposure can be executed and the size of thecamera can be miniaturized (paragraph [0094] in the Japanese patentspecification of the Cited Patent Reference 1).

Also, Cited Patent Reference 2 has described another example of thiskind of the lens barrel cam mechanism according to the related art. TheCited Patent Reference 2 has described technologies concerning acollapsing/extending lens apparatus having a zooming function(hereinafter referred to as a “second related-art example”. The lensapparatus according to the second related-art example includes a lensholding frame for holding a lens and which has a cam follower protrudedtherein and a cam cylinder having a cam groove, engaged with the camfollower of the lens holding frame, formed on the inner peripheralsurface and which is rotated around a lens optical axis wherein avertical surface vertical to the inner peripheral surface of the camcylinder and an inclined surface inclined relative to the verticalsurface are formed on the side surface of the cam groove.

According to the lens apparatus having the above-mentioned arrangementdescribed in the Cited Patent Reference 2, since the vertical surfacevertical to the inner peripheral surface of the cam cylinder and theinclined surface inclined relative to this vertical surface are formedon the side surface of the cam groove, the vertical surface may act as astopper surface relative to the vertical surface. Thus, it is possibleto prevent the cam follower from being disengaged from the cam groove(paragraph [0096] of the Japanese patent specification).

[Cited Patent Reference 1] Japanese unexamined patent publication No.2004-252367

[Cited Patent Reference 2] Japanese unexamined patent publication No.2002-267917

However, in any case of the aforementioned first and second related-artexamples, the cam groove was formed on the inner peripheral surface ofthe cam frame (cam cylinder) and the like, a cam follower of a linearlymovable frame guided linearly was engaged with the cam groove so as tobecome slidable, a drive gear was meshed with a gear portion provided onone side of a rotary axis direction of a cam ring and the drive gear wasrotated by power from a power source to rotate the cam ring, whereby thelinearly movable frame could be moved forward or moved backward inresponse to the rotation direction of the cam ring. As a result, asufficiently large movement amount of the linearly movable frame in therotary axis direction may not be obtained.

It is customary that, in this kind of the lens barrel cam mechanism, themaximum movement amount of the linearly movable frame is determined bythe length of the rotary axis direction of the cam groove provided onthe cam ring. While a gear portion is provided on one side of the rotaryaxis direction of this cam ring, the gear portion should be formed so asnot to interfere with the cam groove. Further, the length of the rotaryaxis direction of the cam groove is also limited by the length of therotating direction of the gear portion. For this reason, the length ofthe rotary axis direction of the cam ring should be selected to be suchone that can secure a length which results from adding a width of thegear portion to the length of the rotary axis direction of the camgroove.

However, in lens barrels for use with recent digital cameras,particularly, in lens barrels having a zooming function, to increase amagnification of an optical system has been in increasing demand andhence it is necessary to increase an amount in which a linearly movableframe such as a lens frame may be moved in the optical axis direction.On the other hand, miniaturization of the lens barrel itself also hasbeen in increasing demand. As a consequence, it becomes necessary toprovide a mechanism by which the movement amount of the optical axisdirection of the linearly movable frame can be increased withoutincreasing the length of the rotary axis direction of the cam ring.

SUMMARY OF THE INVENTION

Problems to be solved in the related-art lens barrel cam mechanism arethat a lens barrel is unavoidably increased in size if the length of therotary axis direction of the cam ring is increased and that, on thecontrary, if a lens barrel is miniaturized, the length of the rotaryaxis direction of the cam ring is unavoidably decreased so that toincrease a magnification of an optical system may not be expected.

According to an aspect of the present invention, there is provided alens barrel cam mechanism including a linearly movable member forholding an optical element and which can be moved in the optical axisdirection of the optical element, the linearly movable member includinga cam follower and a rotary member rotatable relative to the linearlymovable member and which can be also moved relatively to the opticalaxis direction, the rotary member having a cam groove with which the camfollower is slidably engaged formed on its circumferential surface. Inthis lens barrel cam mechanism, the rotary member is rotated to guidethe cam follower with the cam groove so that the linearly movable memberis moved forward and backward in the optical axis direction. This lensbarrel cam mechanism includes a gear portion provided at least a part ofone end of a rotation axis direction of the rotary member, the gearportion being developed at the outside of a radius direction and havingteeth on its outer periphery and a cam groove opening portion providedby opening an end portion of the gear portion side of the cam groove tothe end surface of the rotary member, wherein the cam groove openingportion and the gear portion are provided such that they becomesubstantially coincident with each other on the same vertical planevertical to the optical axis direction.

According to the lens barrel cam mechanism of the present invention,since one end of the cam groove formed on the circumferential surface ofthe rotary member is opened to one end surface of the rotary member andthe cam groove opening portion and the gear portion provided at one endof the rotation axis direction of the rotary member are provided suchthat they become substantially coincident with each other on the samevertical plane vertical to the optical axis direction, it is possible toincrease an amount in which the linearly movable member is moved in therotation axis direction more. As a result, the length of the rotationaxis direction of the linearly movable member can be increased withoutincreasing the length of the rotation axis direction of the rotarymember and hence the whole of the apparatus can be made small in sizeand light in weight.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are respectively perspective views showing a cammechanism of a lens barrel according to a first embodiment of thepresent invention, wherein FIG. 1A shows a barrel retracted state of thelens barrel and FIG. 1B shows a barrel extended state of the lensbarrel;

FIG. 2 is an exploded perspective view of the lens barrel shown in FIG.1;

FIG. 3 is a cross-sectional view showing the barrel retracted state ofthe lens barrel shown in FIG. 1;

FIG. 4 is a cross-sectional view showing the barrel extended state ofthe lens barrel shown in FIG. 1;

FIG. 5 is a perspective view showing a fixed ring according to the lensbarrel shown in FIG. 1;

FIG. 6 is a developed view showing the fixed ring shown in FIG. 5 in adeveloped fashion wherein a cam groove on the inner peripheral surfaceand the like are shown by broken lines;

FIGS. 7A, 7B and 7C show the cam ring according to the lens barrel shownin FIG. 1, wherein FIG. 7A is a perspective view thereof, FIG. 7B is afront view thereof and FIG. 7C is a cross-sectional view taken along theline X-X in FIG. 8A, respectively;

FIGS. 8A and 8B show the cam ring shown in FIG. 7, wherein FIG. 8A is aplan view thereof and FIG. 8B is a bottom view thereof, respectively;

FIGS. 9A and 9B are respectively developed views of the cam ring shownin FIG. 7, wherein FIG. 9A is a developed view showing the cam groove onthe outer peripheral surface and FIG. 9B is a developed view showing thecam groove on the inner peripheral surface by broken lines;

FIG. 10 is a developed view showing a rotation restricted member of thelens barrel shown in FIG. 2 in a developed fashion;

FIG. 11 is a developed view of a linearly movable ring of the lensbarrel shown in FIG. 2, showing the guide groove on the inner peripheralsurface by a broke line;

FIG. 12 is an exploded perspective view showing an automatic exposureapparatus, a space restricting member and a two group ring of the lensbarrel shown in FIG. 2;

FIG. 13 is a developed view of the two group ring of the lens barrelshown in FIG. 2;

FIG. 14 is an exploded perspective view showing the one group ring, thefirst group lens frame and the like of the lens barrel shown in FIG. 2;

FIG. 15 is a developed view of the first group lens frame shown in FIG.14, showing an engagement portion of the inner surface by a broken line;

FIGS. 16A and 16B show a state in which the one group ring and the camring of the lens barrel shown in FIG. 1 are combined, wherein FIG. 16Ais a perspective view showing the assembled state of the one group ringand the cam ring from the bottom side and FIG. 16B is an explanatorydiagram showing a main portion of FIG. 16A in an enlarged-scaled,respectively;

FIGS. 17A and 17B are respectively diagrams to which reference will bemade in explaining a relationship between an assembly body of the onegroup ring and the cam ring shown in FIGS. 16A and 16B and a drive gear,wherein FIG. 17A is a front view thereof and FIG. 17B is a bottom viewthereof;

FIGS. 18A and 18B are respectively diagrams to which reference will bemade in explaining a relationship between the assembly body of the firstgroup cam and the cam ring shown in FIGS. 16A and 16B and the drivegear, wherein FIG. 18A is a right-hand side elevational view and FIG.18B is a cross-sectional view taken along the line Y-Y in FIG. 17B;

FIGS. 19A and 19B are respectively diagrams to which reference will bemade in explaining a relationship between the assembly body of the onegroup ring and the cam ring shown in FIGS. 17A and 17B and the drivegear, wherein FIG. 19A is a perspective view showing a state in which acam follower of the one group ring is completely moved to the outsidefrom a cam groove opening portion of the cam ring and FIG. 19B is a semicross-sectional view thereof;

FIGS. 20A and 20B are respectively diagrams to which reference will bemade in explaining a relationship between the assembly body of the onegroup ring and the cam ring shown in FIGS. 19A and 19B and the drivegear, wherein FIG. 20A is a developed view of a main portion of the onegroup ring and the cam ring and FIG. 20B is a developed view of the camgroove opening portion, showing the gear portion of FIG. 20A in apartially cross-sectional fashion;

FIGS. 21A, 21B and 21C are respectively diagrams to which reference willbe made in explaining a relationship between the assembly body of theone group ring and the cam ring shown in FIGS. 17A and 17B and the drivegear, wherein FIG. 21A is a perspective view showing a state in whichthe cam follower of the one group ring is moved to the cam grooveopening portion of the cam ring, FIG. 21B is a semi cross-sectional viewthereof and FIG. 21C is a developed view of the one group ring, the camring and the cam groove opening portion, showing a part of the gearportion in a cross-sectional fashion;

FIGS. 22A, 22B and 22 c are respectively diagrams to which referencewill be made in explaining a relationship between the assembly body ofthe one group ring and the cam ring shown in FIGS. 17A and 17B and thedrive gear, wherein FIG. 22A is a perspective view showing a state inwhich the cam follower of the one group ring is moved into the camgroove from the cam groove opening portion of the cam ring, FIG. 22B isa semi cross-sectional view thereof and FIG. 22C is a developed view ofthe cam groove opening portion, showing a part of the gear portion in across-sectional fashion;

FIGS. 23A and 23B are respectively diagrams to which reference will bemade in explaining a relationship between the assembly body of the onegroup ring and the cam ring shown in FIGS. 17A and 17B and the drivegear, wherein FIG. 23A is a perspective view showing the state in whichthe cam follower of the one group ring is moved into the cam groove fromthe cam groove opening portion of the cam ring and FIG. 23B is a semicross-sectional view thereof;

FIG. 24 is a developed view to which reference will be made inexplaining a relationship between the assembly body of the one groupring and the cam ring shown in FIGS. 17A and 17B and the drive gear,showing the one group ring and the cam ring shown in FIG. 23A in adeveloped fashion and also showing a part of the gear portion in across-sectional fashion to expose the came groove opening portion;

FIG. 25 is a perspective view to which reference will be made inexplaining a relationship between the assembly body of the one groupring and the cam ring shown in FIGS. 17A and 17B and the drive gear,showing the state in which the cam follower of the one group ring ismoved into the barrel retracted area of the cam groove of the cam ring;

FIGS. 26A and 26B are respectively diagrams to which reference will bemade in explaining a relationship between the assembly body of the onegroup ring shown in FIGS. 17A and 17B and the drive gear, wherein FIG.26A is a semi cross-sectional view thereof and FIG. 26B is a developedview showing the one group ring and the cam ring shown in FIG. 25 in adeveloped fashion and which also shows a part of the gear portion in across-sectional fashion to expose the cam groove opening portion;

FIGS. 27A and 27B are respectively diagrams to which reference will bemade in explaining a relationship between the assembly body of the onegroup ring and the cam groove shown in FIGS. 17A and 17B and the drivegear, wherein FIG. 27A is a perspective view showing the state in whichthe cam follower of the one group ring is moved into the optical zoomingarea of the cam groove of the cam ring and FIG. 27B is a developed viewshowing the one group ring and the cam ring shown in FIG. 27A in adeveloped fashion and which also shows a part of the gear portion toexpose the cam groove opening portion;

FIGS. 28A and 28B are respectively diagrams to which reference will bemade in explaining a relationship between the assembly body of the onegroup ring and the cam groove shown in FIGS. 17A and 17B and the drivegear, wherein FIG. 28A is a perspective view showing the state in whichthe cam follower of the one group ring is passed through the opticalzooming area of the cam groove of the cam ring and FIG. 28B is adeveloped view showing the one group ring and the cam ring shown in FIG.28A in a developed fashion and which also shows a part of the gearportion to expose the cam groove opening portion;

FIGS. 29A, 29B and 29C are respectively diagrams to which reference willbe made in explaining a method of manufacturing a cam groove of the camring shown in FIG. 2, wherein FIG. 29A is a developed view of the camring, FIG. 29B is a developed view showing a part of the gear portionshown in FIG. 29A in a cross-sectional fashion to expose the cam grooveopening portion and FIG. 29C is a cross-sectional view taken along theline Z1-Z1 of FIG. FIG. 29A to thereby expose the cam ring and a mainportion of its injection molding metal mold;

FIGS. 30A and 30B are respectively diagrams to which reference will bemade in explaining a general cam groove manufacturing method, whereinFIG. 30A is a developed view of the cam ring and FIG. 30B is across-sectional view taken along the line Z2-Z2 of FIG. 30A to therebyexpose the cam ring and a main portion of its injection molding metalmold;

FIGS. 31A, 31B and 31C are respectively diagrams to which reference willbe made in explaining a cam groove manufacturing method according to therelated art, wherein FIG. 31A is a developed view of the cam ring, FIG.31B is a developed view showing a part of the gear portion shown in FIG.31A in a cross-sectional fashion to thereby expose the cam grooveopening portion and FIG. 31C is a cross-sectional view taken along theline Z3-Z3 in FIG. 31A to thereby expose the cam ring and a main portionof its injection molding metal mold;

FIG. 32 is a perspective view of a digital still camera showing theembodiment of the camera apparatus using the lens barrel shown in FIG.1, illustrating the state in which the lens barrel is retracted from thefront side;

FIG. 33 is a perspective view of a digital still camera showing theembodiment of the camera apparatus using the lens barrel shown in FIG.1, illustrating the state in which the lens barrel is extended from thefront side;

FIG. 34 is a perspective view of a digital still camera showing theembodiment of the camera apparatus using the lens barrel shown in FIG.1, illustrating the digital still camera from the rear side; and

FIG. 35 is a block diagram showing a schematic arrangement of a digitalstill camera showing the embodiment of the camera apparatus using thelens barrel shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the present invention, a lens barrel cam mechanism in whicha movement amount of a rotary axis direction of a linearly movablemember such as a linearly movable frame can be increased withoutincreasing a length of a rotary axis direction of a rotary member suchas a cam ring so that the whole of the apparatus can be miniaturized andlight-weighted could be realized by simple arrangements.

Embodiments of the present invention will be described below withreference to the accompanying drawings.

FIGS. 1A, 1B to FIG. 35 are diagrams useful for explaining theembodiments of the present invention. FIGS. 1A and 1B are respectivelyperspective views showing a first embodiment of a lens barrel cammechanism according to the present invention, wherein FIG. 1A shows alens barrel retracted state and FIG. 1B shows a lens barrel extendingstate. FIG. 2 is an exploded perspective view of the lens barrel shownin FIGS. 1A and 1B. FIG. 3 is a cross-sectional view showing the lensbarrel retracted state. FIG. 4 is a cross-sectional view showing thelens barrel extending state. FIG. 5 is a perspective view of a fixedring. FIG. 6 is a developed view of the fixed ring. FIGS. 7A, 7B and 7Care a perspective view of a cam ring, a front view of the cam ring and across-sectional view taken along the line X-X in FIG. 8A, respectively.FIGS. 8A and 8B are respectively a plan view of the cam ring and abottom view of the cam ring. FIGS. 9A and 9B are respectively developedviews of an outer peripheral surface of the cam ring and an innerperipheral surface of the cam ring. FIG. 10 is a developed view of arotation restricting member and FIG. 11 is a developed view of alinearly movable ring.

FIG. 12 is a perspective view of an automatic exposure apparatus, aspace restricting member and a two group ring. FIG. 13 is a developedview of the two group ring. FIG. 14 is a perspective view of a one grouplens, a one group ring and the like. FIG. 15 is a developed view of theone group ring. FIGS. 16A and 16B are respectively a perspective viewshowing a combination of the cam ring and the one group ring from thebottom side and a diagram showing main portions of such combination ofthe cam ring and the one group ring in an enlarged-scale. FIGS. 17A and17B are respectively a front view and a bottom view of the samecombination of the cam ring and the one group ring. FIGS. 18A and 18Bare a right-hand side elevational view of the same combination of thecam ring and the one group ring and a longitudinal cross-sectional viewtaken along the line Y-Y in FIG. 17B. Also, FIGS. 19A, 19B to FIGS. 28Ato 28B are diagrams to which reference will be made in explaining apositional relationship between the cam follower of the one group ringand the cam groove of the cam ring. More specifically, FIGS. 19A and 19Bare respectively a perspective view and a cross-sectional view, FIGS.20A and 20B are respectively diagrams used to explain main portions,FIGS. 21A, 21B and 21C are respectively a perspective view, across-sectional view and a diagram used to explain main portions, FIGS.22A, 22B and 22C are respectively a similar perspective view, a similarcross-sectional view and a similar diagram used to explain mainportions, and FIGS. 23A and 23B are respectively a perspective view anda cross-sectional view. FIG. 24 is a diagram used to explain mainportions, FIG. 25 is a perspective view, FIGS. 26A and 26B arerespectively a cross-sectional view and a diagram used to explain mainportions, FIGS. 27A and 27B are respectively a perspective view and adiagram used to explain main portions and FIGS. 28A and 28B arerespectively a perspective view and a diagram used to explain mainportions.

FIGS. 29A, 29B and 29C to FIGS. 31A, 31B and 31C are diagrams used toexplain a relationship between the cam groove of the cam ring and ametal mold, respectively. More specifically, FIGS. 29A, 29B and 29C arerespectively diagrams to which reference will be made in explaining arelationship between the cam groove of the cam ring and the metal moldaccording to the present invention, FIGS. 30A and 30B are respectivelydiagrams used to explain the present invention and FIGS. 31A, 31B and31C are respectively diagrams to which reference will be made inexplaining a relationship between a cam groove of a unsuitable cam ringand a metal mold. FIGS. 32 to 34 are diagrams showing a first embodimentof a digital still camera using a lens barrel shown in FIG. 1 and thelike. More specifically, FIG. 32 is a perspective view showing a digitalstill camera, from the front side, in the state in which the lens barrelthereof is retracted, FIG. 33 is a perspective view showing a digitalstill camera, from the front side, in the state in which the lens barrelthereof is extended and FIG. 34 is a perspective view showing a digitalstill camera from the rear side. FIG. 35 is a block diagram to whichreference will be made in explaining a schematic arrangement of thedigital still camera shown in FIG. 32.

The lens barrel, generally depicted by reference numeral 1 in FIGS. 1 to4, shows a first embodiment of a lens barrel according to the presentinvention. This lens barrel 1 includes a shooting optical systemcomposed of optical elements such as a plurality of lenses and filters,a mechanical system such as ring bodies and frame bodies to supportfixedly or movably constituents of the shooting optical system, a powersupply system such as motors and gears to operate the mechanical systemand the like.

As shown in FIGS. 2 to 4, the shooting optical system of the lens barrel1 is composed of a first lens group 2 formed of a combination of lenseslocated in the sequential order from the object side, an automaticexposure apparatus 3 composed of a shutter and an iris, a second lensgroup 4 formed of a combination of a plurality of lenses, a third lensgroup 5 formed of a combination of one or more than two lenses, alow-pass filter (LPF) 6, an image pickup device (CCD (charge-coupleddevice)) 7 and the like. The first lens group 2 and the second lensgroup 4 are able to demonstrate a zooming function and zoomingoperations of the optical system can be executed by moving the two lensgroups 2 and 4 in the optical axis direction by predetermined amounts.Also, the third lens group 5 is able to demonstrate a focusing functionand focusing operations of the optical system can be executed by movingthe third lens group 5 in the optical axis direction by predeterminedamounts.

The mechanical system of the lens barrel 1 includes a one group ring 10which shows a first specific example of a linearly movable member, a onegroup lens frame 11 to hold the first lens group 2, a two group ring 12which shows a second specific example of a linearly movable member, atwo group lens frame 13 to hold the second lens group 4, a linearlymovable ring 14, a cam ring 15 which shows a specific example of arotary member, a fixed ring 16 fixed to a camera body of a camera suchas a digital still camera, a three group lens frame 17 to hold the thirdlens group 5, a rear lens barrel 18 fixed to the rear portion of thefixed ring 16 and the like. Those elements above are arranged in thesequential order from the object side. Then, a CCD unit 20 including theimage pickup device (CCD) 7 is attached to the rear barrel 18.

Also, the power source system of the lens barrel 1 includes adeceleration gear unit 21 and a drive gear 22 to rotate the cam ring 15,an F motor unit 23 to enable the optical system to carry out focusingoperation and the like. The deceleration gear unit 21 and the F motorunit 23 are attached to an assembly body of the fixed ring 16 and therear barrel 18. Then, the drive gear 22 is supported by the fixed ring16 and the rear barrel 18 so as to rotate freely.

The rear barrel 18 includes an annular rear surface portion 18 a havinga substantially square through-hole 25 defined at its central portion,an inside boss portion 18 b projected on one surface side so as tosurround the circumference pf the through-hole 25 on the rear surfaceportion 18 a and an outside boss portion 18 c projected on one surfaceside so as to continue the outer edge of the rear surface portion 18 a.A unit supporting portion 26 to support the F motor unit 23 is providedat one portion of the outside boss portion 18 c. A seat portion 18 d isformed by denting the peripheral edge of the back side of the insideboss portion 18 b of the rear barrel 18 and the CCD unit 20 is mountedon the seat portion 18 d.

As shown in FIGS. 2 to 4, the CCD unit 20 includes a CCD adapter 28 tohold the CCD (image pickup element) 7 and other constituents, a sealrubber 29, a filter pushing device 30 and the like. The CCD 7 is fixedto the CCD adapter 28. The CCD adapter 28 is formed of a substantiallysquare frame body fitted into the through-hole 25 of the rear barrel 18.The CCD 7 is fixed to the CCD adapter 28 through the seal rubber 29 insuch a manner that its light-receiving surface may be opposed to thecentral opening portion of the CCD adapter 28. The low-pass filter 6 islocated ahead of the light-receiving surface of the CCD 7. The low-passfilter 6 is fixed by the filter pushing device 30 formed of thesubstantially square shaped frame body and it is detachably supported tothe CCD adapter 28. In FIG. 2, reference numeral 31 denotes a flexiblewiring board for use with the CCD 7.

The fixed ring 16 fixed to the front portion of the rear barrel 18 has aconfiguration shown in FIG. 5. The fixed ring 16 is formed of a cylinderbody of a substantially cylindrical shape which serves as the outercasing body of the lens barrel 1. All elements of the shooting opticalsystem can be accommodated within this fixed ring 16. As shown in adeveloped view of FIG. 6, while the optical axis direction front surfaceportion 16 a, which is one end surface of the fixed ring 16, is formedas the flat surface portion vertical to the optical axis direction, theoptical axis direction rear surface portion 16 b, which is the other endsurface of the fixed ring 16, is formed so as to have uneven portions inthe optical axis direction by predetermined stepped portions. The unevenportions of the rear surface portion 16 b are provided so as tocorrespond to the uneven portions of the joint portion of the rearbarrel 18. Further, the fixed ring 16 has a first recess 33 to expose apart of the drive gear 22 and a second recess 34 to expose a part of thethree group lens frame 17.

The first and second recesses 33 and 34 of the fixed ring 16 arerespectively opened to the rear surface portion 16 b. In response to thefirst recess 33, a bearing portion 16 c to support one end of the axialdirection of the supporting shaft 35, which rotatably supports the drivegear 22, is provided on the outer surface of the fixed ring 16. Then, inresponse to the second recess 34, a supporting portion 16 d to supportone portion of an F motor unit 23 is provided on the outer surface ofthe fixed ring 16. Also, totally three cam grooves 37A, 37B and 37C oftwo kinds to support having substantially same cam curves and totallyfive linearly movable guide grooves 38A, 38B and 38C of three kindslinearly extended in the optical axis direction are provided on theinner peripheral surface of the fixed ring 16.

The totally three cam grooves 37A, 37B and 37C of two kinds of the fixedring 16 include an inclined surface portion 37 a spirally extended inthe circumferential direction and a front horizontal portion 37 bcontinued to the side of the front surface portion 16 a of the inclinedsurface portion 37 a′ and which is extended in the circumferentialdirection perpendicular to the optical axis direction. There is alsoincluded a rear horizontal portion 37 c continued to the side of therear surface portion 16 b of the inclined surface portion 37 a which isextended in the circumferential direction perpendicular to the opticalaxis direction and which is further extended in the direction oppositeto the front horizontal portion 37 b. While the respective inclinessurfaces 37 a of the three cam grooves 37A, 38B and 38C are the same inwidth, central rims 39 are provided on the respective inclined surfaces37 a of the two first cam grooves 37A and 37B of the first kind so as tohalve the width direction. A right path 39 a and a left path 39 b, whichare extended in parallel to each other, are formed on the inclinedsurface portions 37 a by the central rims 39.

The totally three cam grooves 37A, 37B and 37C of the two first camgrooves 37A and 37B and one second cam groove 37C of the second kindwhich have different points from a configuration standpoint are disposedon the flat surface crossing the optical axis direction at substantiallyequal interval in the circumferential direction. Three cam followers,which will be described later on, provided on the cam ring 15 areslidably engaged with the totally three cam grooves 37A, 37B and 37C ofthe two kinds having the above-mentioned configurations.

On the other hand, the totally five linearly movable guide grooves 38A,38B and 38C of the three kinds are located on the plane crossing theoptical axis direction at a right angle in parallel to each other suchthat they are spaced apart from each other with a proper space in thecircumferential direction. The two first linearly movable guide grooves38A and 38B of the first kind are adapted to guide two of the linearlymovable ring 14 and the rotation restricted member 80 in the opticalaxis direction. The two first linearly movable guide grooves 38A and 38Aare slidably engaged with cam followers, which will be described lateron, provided on the linearly movable ring 14 and convex portion pieces,which will be described later on, provided on the rotation restrictedmember 80. The two first linearly movable guide grooves 38A and 38A arelocated on one side (left-hand side in FIG. 6) of each of the first camgrooves 37A and 37B with a proper space. Then, the two first linearlymovable guide grooves 38A and 38A are provided so as to cross the fronthorizontal portions 37 b of the first and second cam grooves 37A and37B.

On the other hand, the three second linearly movable guide grooves 38B,38B and 38C of the second kind are adapted to guide the linearly movablering 14 in the optical axis direction together with the two firstlinearly movable guide grooves 38A and 38A. Of the three second linearlymovable guide grooves 38B, 38B and 38C, the two second linearly movableguide grooves 38B and 38B are provided so as to cross the inclinedsurface portions 37 a of the two cam grooves 37A and 37B, whereby notchportions 41 to divide the central projected rim 39 in the obliquedirection are respectively provided on the respective inclined surfaceportions 37 a. On the other hand, the remaining one second linearlymovable guide groove 38C is provided so as to cross the front horizontalportion 37 b of the third cam groove 37C similarly to the first linearlymovable guide groove 38A.

The fixed ring 16 having the above-mentioned arrangement is locatedahead of the rear barrel 18 and it is detachably fixed to the rearbarrel 18 by a plurality of fixed screws. The supporting shaft 35 isheld by the barrel assembly body of the fixed ring 16 and the rearbarrel 18 and part of gear teeth of the drive gear 22 rotatablysupported to the supporting shaft 35 is exposed from the first recess 33to the outside of the barrel assembly body over substantially the wholelength of the gear teeth width direction. A deceleration gear unit 21 isdetachably attached to the bearing portion 16 c of the fixed ring 16 andthe flange portion of the rear barrel 18 so as to cover the exposedportion of this drive gear 22 and fastened and fixed thereto by aplurality of fixed screws.

As shown in FIG. 2, the deceleration gear unit 21 is composed of anoutput gear (not shown) meshed with the drive gear 22, one or more thantwo reduction gears to transmit power to the output gear, a zoom motor44 to rotate the output gear by transmitting power to the zoom motor 44through the reduction gear, a housing 45 to rotatably support the outputgear and other gears and which may fixedly support the zoom motor 44 andthe like. This housing 45 is fastened and fixed to the barrel assemblybody by fixed screws, whereby the deceleration gear unit 21 may beattached so as to be assembled and disassembled. This deceleration gearunit 21 includes a rotation detector composed of a suitable device suchas a rotary encoder to detect revolutions of the zoom motor 44 tothereby output a detected signal.

Also, the unit supporting portion 26 of the rear barrel 18 is formed ofa pair of supporting pieces to support the F motor unit 23 so as to holdthe F motor unit 23. The pair of supporting pieces are projected forwardso as to become substantially parallel to each other with a properspace. The F motor unit 23 held by this unit supporting portion 26 andthe supporting portion 16 d of the fixed ring 16 serves as a powersupply source to enable the lens barrel 1 to carry out focusingoperation. The F motor unit 23 includes a focus motor 46, a motorbracket 47 to fixedly support this focus motor 46, a carriage 48 movablyscrewed to a rotary shaft 46 a of the focus motor 46, a guide bar 49 toguide this carriage 48 substantially parallelly in the axis direction ofthe rotary shaft 46 a and the like.

The motor bracket 47 is formed like a U-shape and the focus motor 46 isfixed to the outside of one raising piece. The rotary shaft 46 a of thefocus motor 46 is formed of a feed screw shaft. Its rotary shaft 46 a isextended through one raising pieces and its tip end portion is supportedto the other raising piece so as to become freely rotatable. Between oneraising piece and the other raising piece, the carriage 48 is screwed tothe rotary shaft 46 a so as to become movable in the axis direction. Aguide bar 49 of which axis line is set substantially parallel to theaxis line of the rotary shaft 46 a is slidably extended through thecarriage 48. Both end portions of the axis direction of the guide bar 49are supported to the motor bracket 47, and the carriage 48 can be guidedby this guide bar 49 so that it can be moved forward and backwardrelative to the optical axis direction.

The third lens group 5 can be moved forward and backward relative to theoptical axis direction by the F motor unit 23 having the above-mentionedarrangement. The third lens group 5 is located ahead of the low-passfilter 6 disposed in front of the CCD 7 and it is held by the threegroup lens frame 17. The third group lens frame 17 is composed of a lensholding portion 17 a to hold the third lens group 5 and an arm portion17 b continued to one side of the lens holding portion 17 a. The armportion 17 b has a slide bearing portion 17 c into which the guide shaft51 is slidably inserted and an engagement portion 17 d which is engagedwith the carriage 48 of the F motor unit 23.

One end of a three group spring 52 formed of a coil spring is engagedwith this three group lens frame 17. The other end of the three groupspring 52 is engaged with the fixed ring 16. Under spring force of thisthree group spring 52, the engagement portion 17 d of the three grouplens frame 17 is constantly urged against the carriage 48 with suitablespring-biasing force. Thus, when the focus motor 46 of the F motor unit23 is driven to rotate, the carriage 48 is guided by the guide bar 49and moved forward and backward in the optical axis direction against thespring force of the three group spring 52 in response to the rotationdirection of the focus motor 46 of the F motor unit 23. As a result, inresponse to a rotation amount of the F motor unit 23, the third lensgroup 5 is moved a predetermined amount in the optical axis direction,thereby resulting in predetermined focusing operation being carried out.

A cam ring 15 is located in the inside of the fixed ring 16. The camring 15 has an arrangement shown in FIGS. 7 to 9. As shown in FIGS. 7 to9, the cam ring 15 has a cylindrical body portion 15 a with an outerdiameter slightly smaller than an inner diameter of the fixed ring 16and a flange portion 15 b continued to one end surface side of its bodyportion 15 a. The flange portion 15 b is developed to the outside of theradial direction. The flange portion 15 b is composed of a first flangeportion 54 a of an arc shape which shares substantially ½ of thecircumferential direction and a second flange portion 54 b of an arcshape located on the opposite side so as to oppose the first flangeportion 54 a. The second flange portion 54 b is formed as an area thatshares substantially ⅙ of the circumferential direction. First andsecond recess portions 55 a and 55 b of substantially the same size asthat of the second flange portion 54 b are formed between the secondflange portion 54 b and the first flange portion 54 a in both sides ofthe circumferential direction.

As shown in FIGS. 8A and 8B, the flange portion 15 b of the cam ring 15has three cam projected portions 57A, 57B and 57C that show the firstembodiment of the cam followers. The three cam projected portions 57A,57B and 57C are disposed in the circumferential direction atsubstantially equal space. The first cam projected portion 57A isprovided on one side of the first flange portion 54 a, the second camprojected portion 57B is provided on the other side of the first flangeportion 54 a and the third cam projected portion 57C is provided on thesecond flange portion 54 b. Of the three cam projected portions 57A, 57Band 57C, the first and second cam projected portions 57A and 57B haveprovided thereon engagement grooves 58 extended in the obliquedirection.

The three cam projected portions 57A, 57B and 57C are slidably engagedwith the three cam grooves 37A, 37B and 37C provided on the innerperipheral surface of the fixed ring 16. The three cam projectedportions 57A, 57B and 57C are formed so as to correspond to the threecam grooves 37A, 37B and 37C. The central projected rims 39 provided onthe first and second cam grooves 37A and 37B are slidably engaged withthe respective engagement grooves 58 provided on the first and secondcam projected portions 57A and 57B. Since the right and left paths 39 aand 39 b are formed by providing the central projected rims 39 on thewide inclined surface portions 37 a of the cam grooves 37A and 37B asdescribed above, even when a recess is produced on the inclined surfaceportion 37 a of the cam groove by the second linearly movable guidegroove 38B extended in the direction crossing the right and left paths39 a and 39 b, the first and second cam projected portions 57A and 57Bare able to smoothly move along the cam grooves 37A and 37B while theyare maintaining cam engagements.

While the three cam projected portions 57A, 57B and 57C are set on thesame plane that crosses at a right angle the axis line of the bodyportion 15 a, as shown in FIGS. 7A and 7B, only the third cam projectedportion 57C is formed thinner than other cam projected portions 57A and57B. A gear portion 60 formed of spur gears is provided on the firstflange portion 54 a of the flange portion 15 b so, as to surround thethird cam projected portion 57C. The gear portion 60 is composed of afirst gear portion 60 a continued to one side of the circumferentialdirection of the first cam projected portion 57A and which has the sametooth width, a second gear portion 60 b formed to the outside of theaxis line direction of the third cam projected portion 57C and which mayhave substantially the same tooth width as that of the first gearportion 60 a and a third gear portion 60 c connecting the first andsecond gear portions 60 a and 60 b and which may have a tooth width thatresults from adding tooth widths of the first and second gear portions60 a and 60 b.

The drive gear 22 is constantly meshed with this gear portion 60 in anyof the gear portions 60 a, 60 b and 60 c. Thus, when the drive gear 22is rotated by actuation of the deceleration gear unit 21, the cam ring15 is rotated left or right in response to the rotation direction of thedrive gear 22. The length of the circumferential direction of this gearportion 60 has gear teeth of the number enough to rotate the cam ring 15by a predetermined angle. For this reason, although the cam ring 15 isalso moved in the axis line direction at the same time the cam ring 15is rotated by the drive gear 22, since the tooth width of the drive gear22 is set to be sufficiently longer than a movement amount (stroke) ofthe axis line direction of the cam ring 15, the cam ring 15 may berotated within a predetermined range in the state in which the drivegear 22 and the gear portion 60 are constantly meshed with each other.

Further, a fin 61 to detect the rotation position of the cam ring 15 isprovided on the first flange portion 54 a of the flange portion 15 b ofthe cam ring 15. The fin 61 is continued to the end portion of the sideof the third cam projected portion 57C of the first flange portion 54 aand it may be formed with a predetermined length in the circumferencedirection. Although not shown, a photosensor is provided on the rearbarrel 18 in order to detect this fin 61. When the photosensor isswitched by movement of the fin 61, it is possible to detect therotation position of the cam ring 15. Thus, when a control apparatus,which will be described later on, processes these information based onrotation position information obtained from this rotation positiondetecting device and detection information obtained from the rotaryencoder provided on the aforementioned deceleration gear unit 21, it ispossible to control a rotation speed and a rotation position of the camring 15.

Furthermore, the first flange portion 54 a of the flange portion 15 b ofthe cam ring 15 has a through-hole 62 that may penetrate the firstflange portion 54 a in the tooth width direction. The through-hole 62 isformed like an arc that may become concentric with respect to the outerperipheral surface of the body portion 15 a or the teeth of the gearportion 60 at the position of the opposite side opposing the secondflange portion 54 b. The end portion of the body portion 15 a facing tothis through-hole 62 is shaped similarly to the first and second recessportions 55 a and 55 b as will be described later on.

Three outer cam grooves 65 having the identical cam curve (trajectory)are provided on the outer periphery of the body portion 15 a of the camgroove 15. The three outer cam grooves 65 are located at substantiallyequal space in the circumferential direction, whereby the one groupframe 10 that supports the first lens group 2 can be operated in theoptical axis direction and the lens barrel 1 can carry out opticalzooming direction and barrel retracting operation. As shown in FIGS. 7A,7B and FIG. 9A, each of the three outer cam grooves 56 is composed of abarrel retracting operation area 66 to apply the barrel retractingoperation and a zooming operation area 67 continued to the barrelretracting operation area 66. The barrel retracting operation area 66 ofthe outer cam groove 65 is spirally extended in the slanting directionwith an angle of inclination of approximately 45 degrees on the outerperipheral surface of the body portion 15 a. One end of this barrelretracting operation area 66 is opened to the end portion of the side ofthe flange portion 15 b of the body portion 15 a and one end of thezooming operation area 67 is continued to the other end of the barrelretracting operation area 66.

The zooming operation area 67 of the outer cam groove 65 includes a zoomgroove portion 67 a formed of a groove shaped like an arc by apredetermined curve, a communicating portion 67 b formed of a groove togently communicate one end of this zoom groove portion 67 a and thebarrel retracting operation area 66 and a closing portion 67 c or anopening portion 67 d to close the other end of the zoom groove portion67 a or to open the other end of the zoom groove portion 67 a to the endportion of the opposite side (anti-flange side) of the side of theflange portion 15 b of the body portion 15 a. The zoom groove portion 67a of the zooming operation area 67 is formed like a convex shaperelative to the side of the flange portion 15 b in the anti-flange sideof the body portion 15 a. The communicating portion 67 b of the zoomingoperation area 67 is formed of a groove of which straight line portionsare continued gently. Also, the closing portion 67 a and the openingportion 67 b are formed of grooves which are continued in thecircumferential direction.

In order to form these communicating portion 67 b and closing portion 67c or opening portion 67 d, three kinds of projected portions 68 a, 68 band 68 c are provided on the anti-flange side of the body portion 15 a.The three first projected portions 68 a provided in response to thecommunicating portion 67 b are formed of trapezoidal portions havinginclined surfaces formed at their both sides. Also, the one secondprojected portion 68 b provided in response to the closing portion 67 cand the two third projected portions 68 c and 68 c provided in responseto the opening portion 67 d are formed of trapezoidal portions havinginclined surfaces formed only at their one sides. On the other hand, asshown by chain double-dashed lines in FIG. 9A, in the two thirdprojected portions 68 c and 68 c, their vertical surfaces are set to theintermediate portion of the cam groove with the result that the camgroove is opened to the end surface side of the body portion 15 a.

The opening end on the side of the flange portion 15 b of the barrelretracting operation area 66 of the outer cam groove 65 forms a grooveopening portion 71 into and from which a cam follower, which will bedescribed later on, of the one group ring 10 is inserted and extracted.A pressing portion 72 to press the cam follower of the one group ring totransmit rotation force of the cam ring 15 to the one group ring 10 isprovided at the outside of the side surface of one cam groove that formsthe cam groove opening portion 71. Further, a holding portion 73 to holdthe cam follower at the position distant from the outer cam groove 65 isprovided on the cam groove opening portion 71 at its opposite side ofthe pressing portion 72.

As shown in FIGS. 7A, 7C and FIG. 9B, three sets of inner cam groovegroups 74 having identical cam curves (trajectories) are located in theinner periphery of the body portion 15 a of the cam ring 15 at an equalspace in the circumferential direction. The three sets of the inner camgrooves 74 are formed of combinations of front inner peripheral camgrooves 75 and rear inner peripheral cam grooves 76 having identical camcurves (trajectories). The three sets of the inner cam grooves 74 enablethe two group frame 12 supporting the second lens group to carry out theoptical axis direction operation and they also enable the lens barrel 1to carry out the optical zooming operation and the barrel retractingoperation. The front inner peripheral cam groove 75 and the rear innerperipheral cam groove 76 are distant from each other by a predeterminedspace in the axis line direction, which is the optical axis direction,of the body portion 15 a. Also, the front inner peripheral cam groove 75and the rear inner peripheral cam groove 76 are set to be slightlydisplaced in the circumferential direction and they are located in thestate in which it is slightly twisted from each other.

Fundamental cam curves of the front inner peripheral cam groove 75 andthe rear inner peripheral cam groove 76 include a first inclined surfaceportion 77 a inclined in the direction similar to the barrel retractingoperation area 66 of the outer cam groove 65 and a second inclinedsurface portion 77 b inclined in the opposite side of the first inclinedsurface portion 77 a and a horizontal portion 77 c to connect one end ofthe first inclined surface portion 77 a and one end of the secondinclined surface portion 77 b in the circumferential direction. Thereare also included an opening portion 77 d continued to the other end ofthe first inclined surface portion 77 a and a circulating portion 77 econtinued to the other end of the second inclined surface portion 77 b,respectively. While the first inclined surface portion 77 a is inclinedat an angle of approximately 45 degrees, its intermediate portion iscurved a little in the rear side. Also, the first inclined surfaceportion 77 a has a predetermined cam curve such that the two group frame12 may be moved forward and backward in unison with the one group frame10 which is moved forward and backward in the optical axis direction bythe zoom groove portion 67 a of the outer cam 65. The second inclinedsurface portion 77 b and the circulating portion 77 e enable the twogroup frame 12 to carry out barrel retracting operation. The secondinclined surface portion 77 b and the circulating portion 77 e arejoined together by a joint portion curved in the front side and they arereturned to the second inclined surface portion 77 b after they weremoved in the circumferential direction within the circulating portion 77e.

The front inner peripheral cam groove 75 and the rear inner peripheralcam groove 76 have the fundamental cam curve as described above. Thefront inner peripheral cam groove 75 includes most of the first inclinedsurface portion 77 a, the horizontal portion 77 c, the second inclinedsurface portion 77 b and the circulating portion 77 d. On the otherhand, the rear inner peripheral cam groove 76 is composed of only a partof the first inclined surface portion 77 a and the opening portion 77 d.More specifically, the first inclined surface portion 77 a of the frontinner peripheral cam groove 75 is opened to the end surface of theprojected portion 68 b in the first inner cam groove group 71 and it isalso opened to the side surfaces of the projected portions 68 c and 68 cin the second and third inner cam groove group 74. A part of thehorizontal portion 77 c of the front inner peripheral cam groove 75 isopened to the end surface of the flange side of the body portion 15 a.

Also, the rear inner peripheral cam groove 76 includes only the openingportion 77 d and the portion of the side of the opening portion 77 d ofthe first inclined surface portion 77 a. More specifically, one end ofthe opening portion 77 d is opened to the end surface on the anti-flangeside of the body portion 15 a and one end of the first inclined surfaceportion 77 a is opened to the end surface of the flange side of the bodyportion 15 a. Then, introducing portions 78 which are widened toward theend so as to facilitate insertion and removable of the cam follower arerespectively formed on respective opening portions of the front innerperipheral cam groove 75 and the rear inner peripheral cam groove 76.

A rotation restricted member 80 which is restricted such that it may beprohibited from being moved in the optical axis direction although itcan be rotated in the rotation direction is fitted into the flangeportion 15 b of the cam ring 15 having the above-mentioned arrangement.As shown in FIGS. 2 and 10, the rotation restricted member 80 includesan annular ring portion 80 a having outer and inner diameterssubstantially the same as those of the body portion 15 a, two linearlymovable guide pieces 80 b and 80 b continued to the inner periphery ofthe ring portion 80 a and two convex portion pieces 80 c and 80 ccontinued to the outer periphery of this rotation restricted member 80.Three recesses 81 are provided on the outer periphery of the ringportion 80 a of this rotation restricted member 80 at an equal space inthe circumferential direction in order to avoid the rotation restrictedmember 80 from contacting with the cam follower, which will be describedlater on, of the one group ring 10.

The two linearly movable guide pieces 80 b and 80 b of the rotationrestricted member 80 are located at positions displaced with each other180 degrees in an opposing fashion and they are also protruded in thedirection vertical to the plane direction of the ring portion 80. Thetwo linearly movable guide pieces 80 b and 80 b are slidably engagedwith two linearly movable guide grooves which will be described lateron. Also, the two convex pieces 80 c and 80 c are projected toward theoutside of the radius direction within a predetermined space in thecircumferential direction. The two convex portion pieces 80 c and 80 care slidably engaged with the aforementioned two first linearly movableguide grooves 38A and 38A of the fixed ring 16. In order to rotatablyaccommodate the ring portion 80 a of the rotation restricted member 80,an annular seat portion 15 c is provided at the inner periphery of theflange portion 15 b of the cam ring 15 as shown in FIGS. 7C and 8B.

The two group ring 12 of which rotation is restricted by the rotationrestricted member 80 and which can be moved only in the optical axisdirection is attached to the inner periphery of the cam ring 15. Asshown in FIGS. 12 and 13, the two group ring 12 includes a cylindricalbody portion 12 a having a cylindrical shape and a two group lens frame12 b which forms an inner flange portion developed toward the inside ofthe radius direction in the intermediate portion of the axis directionof the cylindrical body portion 12 a. A boss portion 12 c is provided atthe inner periphery of the two group lens frame 12 b of the two groupring 12. The second lens group 4 formed of a combination of a pluralityof lenses is attached to the boss portion 12 c.

Two linearly movable guide grooves 83 and 83 with which the two linearlymovable guide pieces 80 b and 80 b of the rotation restricted member 80are slidably engaged are provided on the outer periphery of thecylindrical body portion 12 a of the two group ring 12. The two linearlymovable guide grooves 83 and 83 are located at positions displaced fromeach other 180 degrees and they are shaped like straight line guidegrooves so as to become parallel to the optical axis direction. Further,three sets of cam pin groups 84 which are slidably engaged with threesets of inner cam groove groups 74 provided in the inner periphery ofthe cam ring 15 are provided at the outer periphery of the cylindricalbody portion 12 a. The three sets of cam pin groups 84 are the same inheight in the optical axis direction and they are also located at anequal space in the circumferential direction.

Each of the cam pin groups 84 is composed of a front cam pin 85 and arear cam pin 86 located in the front and back of the optical axisdirection. The front cam pin 85 and the rear cam pin 86 are slightlydisplaced from each other also in the circumferential direction. Thefront cam pin 85 of the cam pin group 84 is engaged with the front innerperipheral cam groove 75 of the inner cam groove group 84 and the rearcam pin 86 is engaged with the rear inner peripheral cam groove 76. Atthat time, while the two linearly movable guide pieces 80 b and 80 b ofthe rotation restricted member 80 are engaged with the two linearlymovable guide grooves 83 and 83 provided in the outer periphery of thetwo group ring 12, the two convex portion pieces 80 c and 80 c of therotation restricted member 80 are slidably engaged with the two firstlinearly movable guide grooves 38A and 38A of the fixed ring 16. Forthis reason, when the cam ring 15 is rotated, the two group ring 12 canbe moved forward and backward only in the optical axis direction alongthe cam curve of the inner cam groove group 74 set by the front innerperipheral cam groove 75 and the rear inner peripheral cam groove 76without being rotated relative to the fixed ring 16.

Operations done by the two group ring 12 and the cam mechanism of thecam ring 15 are as follows. The state in which the two group ring 12 iscompletely accommodated into the cam ring 15 is the non-shooting stateof the camera apparatus. At that time, while the front cam pin 85 islocated at the circulating portion 77 e of the front inner peripheralcam groove 75, the rear cam pin 85 is projected rearward from the bodyportion 15 a so that it is not engaged with the rear inner peripheralcam groove 76. When the cam ring 15 is rotated in the extendingdirection from this non-shooting state, the front cam pin 85 is movedfrom the circulating portion 77 e to the second inclined surface portion77 b by the engagement between the front inner peripheral cam groove 75and the front cam pin 85. As a consequence, the two group ring 12 ismoved forward and backward in the optical axis direction without beingrotated.

When the cam ring 15 is further rotated in the extending direction, thefront cam pin 85 is moved along the second inclined surface portion 77 band reaches the horizontal portion 77 c. Consequently, although thefront cam pin 85 and the front inner peripheral cam groove 75 aredisengaged from the cam engagement, one end of the two group ring 12 isbrought in contact with the rotation restricted member 80 with theresult that the front cam pin 85 can be prevented from being completelydisengaged from the front inner peripheral cam groove 75. Subsequently,when the cam ring 15 is rotated in the extracting direction, the frontcam pin 85 is entered into the first inclined surface 77 a so that thefront cam pin 85 is again engaged with the front inner peripheral camgroove 75 in a cam engagement fashion. Further, when the cam ring 15 isrotated, the rear cam pin 86 approaches the rear inner peripheral camgroove 76 and then the rear cam pin 86 is engaged with the rear innerperipheral cam groove 76 in a cam engagement fashion. Consequently, thefront and rear cam pins 85 and 86 are engaged with the front and rearinner peripheral cam grooves 75 and 76 in a cam engagement fashion.

When the cam ring 15 is further rotated in the extending direction, ifthe two group ring 12 is advanced so much that the front cam pin 85 ispassed through the first inclined surface 77 a, then the cam engagementbetween the front cam pin 85 and the front inner peripheral cam groove75 is disengaged. However, in this case, the rear cam pin 86 is engagedwith the rear inner peripheral cam groove 76 in a cam engagementfashion, whereby a further cam engagement can be maintained. Therefore,it is possible to further advance the two group ring 12 greatly by thecam engagement of only the rear cam pin 86 and the rear inner peripheralcam groove 76. At that time, since the introducing portions 78 which arewidened in their ends are formed on the respective opening portions ofthe front and rear ends of the front inner peripheral cam groove 75 andthe rear end of the rear inner peripheral cam groove 76, switchingoperations done when the cam engagement between the front cam pin 85 andthe rear cam pin 86 can be carried out smoothly. It should be noted thatoperations done when the shooting state is changed to the non-shootingstate become opposite to the aforementioned operations.

The automatic exposure apparatus 3 is attached to the front portion ofthe two group ring 12 in such a manner that it can be moved toward theoptical axis direction by a predetermined distance while its movement inthe rotation direction is being restricted. The automatic exposureapparatus 3 is the optical apparatus having a shutter function to shutand open a light path through which light passes, a variable irisfunction to change a diameter of the light path and a filter function toinsert and extract a filter into and from the light path. This automaticexposure apparatus 3 includes an annular hollow holder 88, and a shutterdiaphragm, an iris diaphragm and a filter diaphragm are disposed arounda central hole so as to surround the central holes as shown in FIG. 12.Three guide protrusions 89 are disposed on the outer surface of theholder 88 at an equal spacing in the circumferential direction.

The two group ring 12 includes three protruded receiving portions 91corresponding to the three guide protrusions 89 of the automaticexposure apparatus 3. The guide protrusions 89 are respectively engagedwith these protruded receiving portions 91, whereby the automaticexposure apparatus 3 can be moved forward and backward in the opticalaxis direction by an amount of the spacing within the protrudedreceiving portion 91. Further, a plurality of compression coil springs92 which show a specific example of a resilient member to bias theautomatic exposure apparatus 3 and the two group ring 12 under springforce are interposed between the automatic exposure apparatus 3 and thetwo group ring 12. The position at which a plurality of compression coilsprings 92 are extended most so that the automatic exposure apparatus 3may become distant from the two group ring 12 most is the position ofthe shooting state. Conversely, the position at which a plurality ofcompression coil springs 92 are contracted most so that the automaticexposure apparatus 3 may become closet to the two group ring 12 is theposition of the non-shooting state.

In the non-shooting state, the boss portion 12 c of the two group ring12 is entered into the central hole 88 a of the holder 88 of theautomatic exposure apparatus 3. To this end, the diameter of the centralhole 88 a is set to be larger than that of the boss portion 12 c.Further, the tip end surface of the boss portion 12 c is configured toextend through the central hole 88 a and to become substantially flushwith the front surface of the holder 88. Therefore, in the non-shootingstate, diaphragms of the shutter function, the variable iris functionand the filter function of the automatic exposure apparatus 3 should bemoved from the central hole 88 to the outside. In order to maintainthese functions, a space restricting member 94 is interposed between theautomatic exposure apparatus 3 and the two group ring 12.

The space restricting member 94 has an arrangement shown in FIG. 12. Thespace restricting member 94 includes a ring portion 94 a rotatablyfitted into the boss portion 12 c of two group ring 12 and a leverportion 94 b formed so as to project from the outer periphery of thering portion 94 a to the outside of the radius direction. A camprotrusion 94 c that is extended in the direction vertical to thedirection of the plane of the ring portion 94 a is provided at the tipend of the lever portion 94. This cam protrusion 94 c is extendedthrough a hole defined in the two group lens frame 12 b to the oppositeside of the automatic exposure apparatus 3 in the state in which thespace restricting member 94 is assembled into the two group ring 12.Then, the space restricting member 94 is constantly biased in apredetermined rotation direction by a torsion spring 95 which shows aspecific example of a resilient member.

Further, the ring portion 94 a of the space restricting member 94includes three stopper portions 94 d to prevent the automatic exposureapparatus 3 and the two group ring 12 from approaching each other morethan a predetermined amount. The three stopper portions 94 d are locatedat substantially an equal space in the circumferential direction on thesurface opposite to the side in which the cam protrusion 94 c of thering portion 94 a is protruded. When the lens barrel 1 is set to thestate just before the non-shooting state, the cam protrusion 94 c of thespace restricting member 94 is brought in contact with the camprotrusion 18 e protruded forward from the rear surface portion 18 a ofthe rear barrel 18. When the lens barrel 1 is further moved to thedirection of the non-shooting state from this state, the spacerestricting member 94 is rotated in accordance with the cam surface ofthe cam protrusion 94 c and the cam surface of the cam protrusion 18 eby a predetermined amount.

As a result, when the space restricting member 94 is rotated by apredetermined amount, the three stopper portions 94 d are moved to theposition at which a stopper surface (not that the automatic exposureapparatus 3 and the two group frame 12 are released from beingspace-restricted. As a consequence, since the automatic exposureapparatus 3 becomes able to move to the direction in which it mayapproach the two group ring 12, it becomes possible to shorten thelength of the optical axis direction 12 by accommodating the two groupring 12 into the automatic exposure apparatus 3. On the other hand, inthe shooting state, the three stopper portions 94 d of the spacerestricting member 94 are interposed between the automatic exposureapparatus 3 and the two group ring 12. Therefore, it is possible toprevent the space between the automatic exposure apparatus 3 and the twogroup ring 12 from being decreased more than necessity by restrictingthe space therebetween with the stopper portions 94 d.

According to the above-mentioned arrangement, even when unintentionalexternal force and shock is applied to the lens barrel 1 in the shootingstate, the space between the automatic exposure apparatus 3 and the twogroup ring 12 can be prevented from being narrowed more than apredetermined amount. For this reason, the automatic exposure apparatus3 can be prevented from being urged against the two group ring 12,whereby suitable functions such as the shutter function and the variableiris function of the automatic exposure apparatus 3 can be protected. Inaddition, the thickness from the two group ring 12 to the automaticexposure apparatus 3 in the non-shooting state can be decreased ascompared with the thickness in the shooting state.

As shown in FIGS. 2 and 3 and the like, the one group ring 10 isrelatively attached to the outer periphery of the body portion 15 a ofthe cam ring 15 so as to become rotatable freely. As shown in FIGS. 2and 4 and so on, the one group ring 10 includes a cylindrical bodyportion 10 a into which the body portion 15 a is inserted inside, anouter flange portion 10 b continued to one end of the axial direction ofthe cylindrical body portion 10 a and which is developed to the outsideof the radius direction and an inner flange portion 10 c continued tothe front side serving as the other end of the axial direction of thecylindrical body portion 10 a and which is continued to the inside ofthe radius direction. Further, three brackets 10 d projected in thebackward of the optical axis direction are provided on the cylindricalbody portion 10 a of the one group ring 10 at an equal space in thecircumferential direction.

The three brackets 10 d include guide convex portions 97 projectedtoward the outside of the radius direction and cam pins 98 which show aspecific example of the cam follower projected toward the inside of theradius direction. Although the guide convex portions 97 and the cam pins98 are located so as to overlap with each other at the same position,while the guide convex portions 97 are integrally formed with part ofthe brackets 10 d, the cam pins 98 are formed integrally with thebrackets 10 d by inserting different members thereto with pressure. Thatis, the guide convex portion 97 is formed of a block-like portionextended in the optical axis direction and the three guide convexportions 97 are slidably engaged with a linearly movable guide groove,which will be described later on, of the linearly movable ring 14.

The three cam pins 98 are cam followers which are slidably engaged withthe three outer cam grooves 65 provided at the outer periphery of thebody portion 15 a of the cam ring 15. The cam pin 98 includes a pin headportion 98 a in slidable contact with the outer cam groove 65, a fixedportion 98 b fitted into an attachment hole of the bracket 10 d withpressure and a flange portion 98 c provided between the fixed portion 98b and the pin head portion 98 a. The flange portion 98 c plays a role tolimit the insertion depth of the fixed portion 98 b to thereby hold aprojected amount of the pin head portion 65 a at a predetermined amount.An operation surface 99 with which the pressing portion 72 of the camring 15 contacts is provided at one side surface of the bracket 10 d inwhich suitable members such as the cam pin 98 are provided. Theoperation surface 99 is set to an inclination angle corresponding to theinclined surface of the pressing portion 72 and this inclination angleis approximately 45 degrees.

This one group ring 10 is attached to the inner periphery of thelinearly movable ring 14 in such a manner that it can be restricted frommoving toward the rotation direction and that it can be moved only inthe optical axis direction. As shown in FIGS. 2 and 11, the linearlymovable ring 14 includes a cylindrical body portion 14 a into which theone group ring 10 is inserted and an outer flange portion 14 b providedat one end of the optical axis direction of the cylindrical body portion14 a and which is also developed at the outside of the radius direction.The outer flange portion 14 b includes five projected portions 14 cwhich are slidably engaged with the five linearly movable guide grooves38A, 38A, 38B, 38B and 38C provided on the inner periphery of the fixedring 16. The five projected portions 14 c are located at positionscorresponding to the five linearly movable guide grooves 38A, 38A, 38B,38B and 38C, respectively. Although all of five linearly movable guidegrooves 38A, 38A, 38B, 38B and 38C of the fixed ring 16 are crossing thecam grooves 37A, 37B and 37C, the optical axis directions of the fivecrossing places are not all identical in the five linearly movable guidegrooves 38A, 38A, 38B, 38B and 38C so that five engagements of the fiveprojected portions 14 c of the linearly movable ring 14 and the fivelinearly movable guide grooves 38A, 38A, 38B, 38B and 38C of the fixedring 16 can be prevented from being disengaged at the same time. As aresult, the linearly movable ring 14 can be smoothly moved forward andbackward in the optical axis direction relative to the fixed ring 16.More specifically, at the optical axis direction in which the twolinearly movable guide grooves 38B and 38B of the fixed ring 16 and thecam grooves 37A and 38B are crossing each other, of the five projectedportions 14 c of the linearly movable ring 14, engagements of the twoprojected portions 14 c are broken and the remaining three projectedportions 14 c can maintain their engagements with the linearly movableguide grooves 38A, 38A and 38C. On the other hand, at the optical axisdirection in which the three linearly movable guide grooves 38A, 38B and38C of the fixed ring 16 and the cam grooves 37A, 37B and 37C arecrossing each other, of the five projected portions 14 c of the linearlymovable ring 14, engagements of the three projected portions 14 arebroken and the remaining two projected portions 14 c can maintain theirengagements with the linearly movable guide grooves 38B and 38B.

Three linearly movable guide grooves 101 which are slidably engaged withthree guide convex portions 97 provided on the outer periphery of onegroup ring 10 are provided at the inner periphery of the cylindricalbody portion 14 a of the linearly movable ring 14. The three linearlymovable guide grooves 101 are located at substantially an equal space inthe circumferential direction and they are linearly extended in theoptical axis direction in parallel to each other. In each of thelinearly movable guide grooves 101, while the end portion of the side ofthe outer flange portion 14 b is opened to the end surface of thecylindrical body portion 14 a, the end portion of its opposite side isinterrupted at the intermediate portion of the optical axis direction.Thus, while the one group ring 10 is able to enter the linearly movablering 14 on the side of the outer flange portion 14 b, it comes to a deadend on the tip end side of the side of the anti-outer flange portion 14b so that the one group ring 10 can be prevented from being dropped fromthe tip end side unintentionally.

A decorative ring 102 for use with the linearly movable ring 14 so as tomainly save an appearance of the lens barrel 1 is attached to andintegrally formed with the outer periphery of the linearly movable ring14. Then, the cam ring 15 is attached to the inner periphery of thelinearly movable ring 14 attached to the inner periphery of the fixedring 16.

More specifically, the three cam pins 98 provided at the inner peripheryof the one group ring 10 are slidably engaged with the three outer camgrooves 74 provided at the outer periphery of the cam ring 15,respectively. Then, the three guide convex portions 97 provided at theouter periphery of the one group ring 10 are slidably engaged with thethree linearly movable guide grooves 101 formed in the inner peripheryof the linearly movable ring 14. Further, the five projected portions 14c projected to the outer periphery of the linearly movable ring 14 areslidably engaged with the five linearly movable guide grooves 38A, 38A,38B, 38B and 38C provided in the inner periphery of the fixed ring 16,respectively. Concurrently therewith, the three cam projected portions57A, 57B and 57C provided on the flange portion 15 b of the cam ring 15are slidably engaged with the three cam grooves 37A, 38B and 37Cprovided in the inner periphery of the fixed ring 16, respectively.Further, the two convex portion pieces 80 c of the rotation restrictedmember 80 held on the cam ring 15 are slidably engaged with the twolinearly movable guide grooves 38A and 38A provided in the innerperiphery of the fixed ring 16, respectively.

As described above, in the linearly movable ring 14 and the rotationrestricted member 80, since the five projected portions 14 c of thelinearly movable ring 14 are engaged with the five linearly movableguide grooves 38A, 38A, 38B, 38B and 38C of the fixed ring 16 and thetwo convex portion pieces 80 c of the rotation restricted member 80 areengaged with the two linearly movable guide grooves 38A and 38A of thefixed ring 16, the linearly movable ring 14 and the rotation restrictedmember 80 can be prevented from being rotated relative to the fixed ring16. Further, they become integral together by only a distance in whichthe cam ring 15 is moved in the optical axis direction and thereby movedtoward the optical axis direction. Also, since the three guide convexportions 97 of the one group ring 10 are engaged with the three linearlymovable guide grooves 101 of the linearly movable ring 14, the one groupring 10 can be moved forward and backward in the optical axis directionin response to a rotation amount of the cam ring 15 without beingrotated. It should be noted that the one group ring 10 and the two groupring 12 are biased so as to be attracted with each other in the opticalaxis direction under spring force of a plurality of coil springs 103which show a specific example of a resilient member.

Operations of the one group ring 10 and the cam mechanism of the camring 15 are as follows. As shown in FIGS. 16A, 16B, FIGS. 17A, 17B andFIGS. 18A, 18B, the state in which the one group ring 10 is completelyretracted into the cam ring 15 is the non-shooting state of the cameraapparatus. At that time, the rear end side of the outer cam groove 65 ofthe cam ring 15 is opened and the cam pin 98 in this camera non-shootingstate is located at the holding portion 73 of the opened cam grooveopening portion 71 and it is therefore disengaged from the outer camgroove 65. When the cam ring 15 is rotated in the extending directionfrom this state, the pressing portion 72 of the cam ring 15 collideswith the operation surface 99 of the bracket 10 d of the one group ring10 so that the one group ring 10 is elevated by the thus inclinedoperation surface 99. The one group ring 10 is moved in the optical axisdirection by pushing and elevating force of this cam ring 15 withoutbeing rotated relative to the fixed ring 16.

Further, when the cam ring 15 is rotated to an extent that the cam ring15 lies in the extending direction, the cam pin 98 is engaged with theouter cam groove 65. When the cam ring 15 is further rotated, thecontacted state between the pressing portion 72 of the cam ring 15 andthe operation surface 99 of the one group ring 10 is released. Afterthat, the one group ring 10 can be moved forward and backward in theoptical axis direction along the cam curve (trajectory) of the outer camgroove 65 in response to the rotation amount of the cam ring 15 withoutbeing rotated relative to the fixed ring 16. At that time, since theopen end of the outer cam groove 65 is increased in width to the end, itis possible to reliably and easily engage the cam pin 98 with the outercam groove 65. It should be noted that movements obtained when thecamera apparatus is changed from the shooting state to the non-shootingstate become opposite to the aforementioned operations.

As shown in FIGS. 2 and 14, a plurality of staircase-like fixed portions105 of which heights are changed in the optical axis direction areprovided on the inner flange portion 10 c provided on the innerperiphery of the one group ring 10. The one group lens frame 11 is heldto and fixed to the one group ring 10 by using a plurality of fixedportions 105 provided on the inner flange portion 10 c. The one grouplens frame 11 is formed of an annular member fitted into the innerflange portion 10 c and the first lens group 2 formed of a combinationof a plurality of lenses is held at the inner periphery of the one grouplens frame 11. A plurality of sets (three sets in this embodiment) ofsandwiching protrusions 106 to fix the one group lens frame 11 to theone group ring 10 are provided on the outer periphery of the one grouplens frame 11 at substantially an equal space in the circumferentialdirection.

Each of the sandwiching protrusions 106 is formed of a combination of afront protrusion 106 a and a rear protrusion 106 b which are located inthe front and back of the optical axis direction at a predeterminedclearance. The front protrusion 106 a and the rear protrusion 106 b arelocated with a small displacement in the circumferential direction. Whenthe fixed portion 105 of the inner flange portion 10 c is sandwichedfrom front and back by a plurality of sandwiching protrusions 106 havingthe above-mentioned arrangement, the one group lens frame 11 is fixed toone group ring 10. In this fixed state, when the one group lens frame 11is rotated in the circumferential direction, the one group lens frame 11may be moved forward and backward in the optical axis direction by anamount of a stepped portion of the staircase shape in response to therotation amount. Reference numeral 108 in FIG. 14 and the like denotes adecorative ring which covers the circumference of the first lens group2.

As shown in FIGS. 2 to 4, a lens barrier unit 110 to close the lightpath serving as the shooting opening to thereby protect the shootingoptical system in the non-shooting state is provided at the front end ofthe one group ring 10. The lens barrier unit 110 includes an annularbarrier main body 110 a, a pair of opening and closing diaphragms 10 brotatably supported to the barrier main body 110 a, a diaphragm openingand closing mechanism 110 c to open and close the opening and closingdiaphragms 10 b and the like. A plurality of engagement clicks 110 d areprovided on the barrier main body 110 a at substantially an equal spacein the circumferential direction. The lens barrier unit 110 is fixed tothe one group ring 10 by engaging those engagement clicks 110 d with theinner periphery of the cylindrical body portion 10 a.

The diaphragm opening and closing mechanism 110 c of the lens barrierunit 110 includes a drive arm to rotate the opening and closingdiaphragms 10 b although not shown. The drive arm may be rotated byrelative movement toward the optical axis direction. Accordingly, whenthe drive arm is rotated by the relative movement toward the opticalaxis direction, the light path of the lens barrier unit 110 can beopened and closed by opening and closing the opening and closingdiaphragms 10 b.

Also, as shown in FIGS. 2, 3 and 4, a decorative ring 112 to keep anappearance of the lens barrel 1 is attached to the one group ring 10.This decorative ring 12 may play a role similar to that of thedecorative ring 102 for use with the linearly movable ring 14 and it isattached to the one group ring 10, thereby being integrally fixed to theone group ring 10. While suitable materials of these decorative rings112 and 102 are metals such as aluminum alloy and stainless steel, it isneedless to say that engineering plastic can be used as theabove-mentioned materials. Also, while suitable materials of the onegroup ring 10, the one group lens frame 11, the two group ring 12, thelinearly movable ring 14, the cam ring 15, the fixed ring 16, the threegroup lens frame 17 and the rear barrel 18 are fiber reinforced plastic(FRP), it is needless to say that ABS (acrylonitrile-butadiene-styrene)resin and other engineering plastic can be used as the above-mentionedmaterials and that aluminum alloy and other metal can be used as theabove-mentioned materials.

As shown in FIGS. 3 and 4, the flexible wiring board 15 is electricallyconnected to the automatic exposure apparatus 3. One end of the flexiblewiring board 115 is connected to a wiring circuit of an actuator todrive the shutter mechanism, the variable iris mechanism of theautomatic exposure apparatus 3 and the like. The other end of theflexible wiring board 115 is electrically connected to an electric powersource installed at the outside of the lens barrel 1. One end of theflexible wiring board 115 is laid within the two group ring 12 withproper slackening such that a bad influence may not be caused by its ownreaction force even when a space between the automatic exposureapparatus 3 and the two group ring 12 is changed.

As described above, the outer cam groove 65 of the cam ring 15 isconfigured in such a manner that the automatic exposure apparatus 3assembled into the two group ring 12 is urged against the two group ring12 just before the non-shooting state and that the space between the twogroup ring 12 and the automatic exposure apparatus 3 may be minimized inthe non-shooting state. As a consequence, it becomes possible to realizea thinner collapsing type lens barrel as compared with the related-artlens barrel in the non-shooting state. FIGS. 19A, 19B, FIGS. 20A, 20B,FIGS. 21A, 21B, 21C, FIGS. 22A, 22B, 22C, FIGS. 23A, 23B, FIG. 24, FIG.25, FIGS. 26A, 26B, FIGS. 27A, 27B and FIGS. 28A, 28B are diagrams towhich reference will be made in explaining the state in which the lensbarrel 1 is extended from the barrel retracted state and changed to thezooming state. Next, the changed states of the lens barrel 1 will bedescribed in brief.

FIGS. 19A, 19B and FIGS. 20A, 20B show the state in which the lensbarrel 1 is placed in the barrel retracted state. In this state, thethree cam pins 98 of the one group ring 10 are accommodated within theholding portion 73 provided outside the cam groove opening portion 71opened to the side of the flange portion 15 b in the barrel retractingoperation area 66 of the outer cam groove 65 of the cam groove 15. Atthat time, of the three cam pins 98, the two cam pins 98 are located atthe two recess portions 55 a and 55 b of the flange portion 15 b. On theother hand, the remaining one cam pin 98 is inserted into thethrough-hole 62 defined in the first flange portion 54 a and thereby itis exposed to the rear surface side of the flange portion 15 b as shownin FIGS. 16A and 16B.

Operations in which the one group ring 10 is moved forward and backwardare executed when the cam ring 15 is rotated relative to the one groupring 10 based on rotation of the drive gear 22 by the deceleration gearunit 21. First, the extending operation of the one group ring 10 will bedescribed. When the cam ring 15 is rotated in the extending direction,first, the cam ring 15 is changed to the states shown in FIGS. 21A, 21Band 21C. At that time, the pressing portion 72 provided on the cam ring15 contacts with the inclined operation surface 99 of the bracket 10 dprovided on the one group ring 10 so that the pressing portion 72presses the operation surface 99 in the circumferential direction. Atthat time, force directing toward the optical axis direction isgenerated by actions of the inclined surface of the pressing portion 72and the inclined surface of the operation surface 99.

The pressing portion 72 contacts with the operation surface 99 to changethe cam pin 98 from the states shown in FIGS. 21A, 21B and 21C to thestates shown in FIGS. 22A, 22B and 22C. More specifically, the contactof the pressing portion 72 and the operation surface 99 is graduallymoved from the tip end to the base end side of the bracket 10 d. Then,when the cam pin 98 is completely inserted into the outer cam groove 65,as shown in FIGS. 23A, 23B and FIG. 24, the contact between the pressingportion 72 and the operation surface 99 is changed to a contact betweenthe cam pin 98 and one side surface of the outer cam groove 65. Afterthat, by the contact between the cam pin 98 and the outer cam groove 65,the cam pin 98 is guided by the outer cam groove 65 and hence opticalzooming operations shown in FIG. 25, FIGS. 26A, 26B, FIGS. 27A, 27B andFIGS. 28A, 28B are executed.

FIG. 25 and FIGS. 26A and 26B show the states in which the lens barrel 1is changed from the barrel retracting operation area 66 to the zoomingoperation area 67. When the lens barrel 1 is changed from these statesto the states shown in FIGS. 27A and 27B, since such change is a changein which the first lens group 2 approaches the second lens group 4, thewide angle (wide-angle lens) side is increased. On the other hand, whenthe lens barrel 1 is changed from the states shown in FIGS. 27A and 27Bto the states shown in FIGS. 28A and 28B, since such change is a changein which the first lens group 2 comes away from the second lens group 4,a telephoto (telephoto lens) side is increased.

The retracting operations of the one group ring 10 are carried out byoperations opposite to those shown in FIGS. 19A, 19B to FIGS. 28A and28B.

FIGS. 29A, 29B and 29C are diagrams to which reference will be made inexplaining a metal mold to form the aforementioned inventive cam ring 15by injection molding. FIGS. 30A and 30B are diagrams useful forexplaining a general metal mold and FIGS. 31A, 31B and 31C are diagramsuseful for explaining a metal mold which is located at the intermediateposition between a general metal mold and the metal mold concerning theinventive cam ring 15.

As shown in FIGS. 30A and 30B, having considered a cam ring 15A having ageneral outer peripheral gear train in which a gear portion is providedon the outer periphery of the flange portion, it is to be understoodthat the cam groove 65 and the gear portion 60 formed on the cam ring15A are placed in a positional relationship developed as shown in FIG.30A. Assuming now that G is a length of the optical axis direction ofthe cam ring 15A and that K is a tooth width of the gear portion 60,then in order to prevent the cam groove 65 and the gear portion 60 frominterfering with each other, a clearance M should be produced betweenthe gear portion 60 and the cam groove 65 so that the cam groove 65should be prevented from contacting with the gear portion 60. At thattime, the length of the optical axis direction of the cam groove 65becomes H1.

In this case, as shown in FIG. 30B, when a general split metal mold 201is used, it is possible to easily produce the cam ring 15A by injectionmolding. The split metal mold 201 schematically shows a metal mold slidecore required when the cam ring 15A having a general outer peripheralgear train is formed by injection-molding a synthetic resin. The splitmetal mold 21 has a projected rim corresponding to the shape of the camgroove in order to form the cam groove 65 of the cam ring 15A in aninverted fashion. When this split metal mold 201 is parallelly moved inthe plane direction vertical to the rotary shaft of the cam ring 15Aafter injection molding, the cam groove 65 can be formed bymold-releasing the cam ring 15A.

However, when the split metal mold 201 shown in FIG. 30B is in use, thelength H1 of the cam groove 65 of the cam ring 15A may not be obtainedsufficiently. In order to increase the length of the cam ring 65, it isconsidered that the positional relationship between the cam groove 65and the gear portion 60 should be set to the state shown in FIG. 31A or31B. FIG. 31A shows the inventive cam ring 15 and FIG. 31B shows suchone in which the through-hole 62 is bored through the gear portion 60 ofthe cam ring 15A shown in FIG. 30A, the cam groove 65 being extended upto the inside of the through-hole 62. In the case of the cam ring 15shown in FIG. 31A, it is possible to extend the length of the cam groove65 by a length N. In the case of a cam ring 15B shown in FIG. 31B, it ispossible to extend the length of the cam groove 65 by a length N1.

However, in any case of FIGS. 31A and 31B, in a general metal mold slidecore 204 shown in FIG. 30B, since a part 205 enters into thethrough-hole 62 defined on the inside of the gear portion 60, so-calledundercut is produced in that portion. For this reason, the cam ring 15(or 15B) may not be molded continuously by this metal mold slide core204.

On the other hand, continuous molding is made possible by using twosplit metal molds 207 and 208 shown in FIG. 29C. To this end, the camgroove 65 is divided into a portion which does not overlap with the gearportion 60 in the optical axis direction and a portion which overlapswith the gear portion 60 in the optical axis direction. Then, thenon-overlapping portion of the cam groove 65 is provided on the firstsplit metal mold 207 and the overlapping portion of the cam groove 65 isprovided on the second split metal mold 208. As a result, while thefirst split metal mold 207 is being moved to the lateral side, itbecomes possible to move the second split metal mold 208 in the lowerdirection perpendicular to the direction in which the first split metalmold 207 is moved.

When the above-mentioned metal mold is in use, since the length H of theoptical axis direction of the cam groove 65 can be prevented from beinglimited by the tooth width K of the gear portion 60, the cam groove 15can be extended without increasing the length G of the optical axisdirection of the cam ring 15 and it is possible to maintain asufficiently large movement amount in the optical axis direction of theone group ring 10. Accordingly, assuming now that the length of the camgroove is not changed, then the length G of the optical axis directionof the cam ring 15 can be decreased more, whereby the lens barrel can beminiaturized.

A digital still camera 300 shown in FIGS. 32 to 34 shows a firstembodiment of a camera apparatus configured by using the aforementionedlens barrel 1 according to the present invention. This digital stillcamera 300 may use a semiconductor recording media as an informationrecording medium, may convert an optical image from an object into anelectric signal by a CCD (charge-coupled device (solid-state imagepickup device)) and may record such electric signal on the semiconductorrecording media or may display such electric signal on a flat displaypanel 302 that is a display apparatus such as a liquid-crystal display.

This digital still camera 300 includes the above-described lens barrel 1to pick up an object image as light to introduce this light into a CCD(charge-coupled device) serving as an image pickup device, a camera case301 in which the lens barrel 1 and other apparatus and equipment arehoused, a flat display panel 302 serving as a display apparatus formedof a liquid-crystal display and the like to display an image based on avideo signal outputted from the CCD, a control apparatus to controloperations of the lens barrel 1, displaying on the flat display panel302 and the like, a battery power supply (not shown) and the like.

The camera case 301 is formed of an oblong flat container and it iscomposed of a front case 303 and a rear case 304 which are put one uponanother in the front and back direction, a center case 305 formed of asubstantially rectangular frame body interposed between the front case303 and the rear case 304 and the like. An annular decorative ring 306is attached to the front surface of the front case 303 at its positionslightly displaced from the center to one side and the one group ring 10of the front side of the lens barrel 1 is opposed to a central hole 307of the decorative ring 306 such that it can be moved forward andbackward and the like.

FIG. 32 shows the non-shooting state (barrel retracting state) of thelens barrel 1 and which corresponds to FIG. 1A. A substantially whole ofthe front surface of the lens barrel 1 is configured to becomesubstantially flush with the front surface of the front case 303. Also,FIG. 33 shows the shooting state (extended state) of the lens barrel 1and which corresponds to FIG. 1B. As shown in FIG. 33, the decorativering 112 including the one group ring 10 and the decorative ring 102including the linearly movable ring 14 are extended in an insertedfashion.

A light-emitting portion 307 of a flash apparatus and alight-emitting/light-receiving portion 308 of an auto-focus mechanismare provided on the slanting upper portion of the lens barrel 1 of thefront case 303. Also, a power button 309, a shutter release button 310,sound collecting holes 311 of a sound collecting apparatus such as amicrophone and the like are formed on the upper surface of the centercase 305. Further, a battery compartment portion in which batteriesserving as a power supply are detachably accommodated is provided on oneside surface portion of the center case 305 and a battery lid 312 isdetachably engaged with the battery compartment portion. Then, speakerholes 313 for use with a speaker apparatus are formed on the sidesurface portion of the opposite side of the battery lid 312 of thecenter case 305.

A large display window 315 is opened at the rear case 304 and the flatdisplay panel 302 is attached to the display window 315. The flatdisplay panel 302 has a touch operation function by which a user is ableto operate the camera apparatus by touching the display surface. Variouskinds of operation switches are provided on one side of the flat displaypanel 302 of the rear case 304. While a mode change-over switch 316 toselect function modes (still picture, moving picture, playback, etc.),an optical zoom operation button 317 to execute zoom operations, a menubutton 317 to select various kinds of menus, a display switching button319 to switch display on the screen and the like may be enumerated asthe operation switches, the operation switches are not limited theretoand a direction key to move a cursor for selecting menus, a picturebutton to switch picture sizes and to delete pictures can also beprovided as the operation switches.

A control apparatus to control the lens barrel 1, the flat display panel302 and the like is housed within the camera case 301 having theabove-mentioned arrangement. The control apparatus is configured bymounting a predetermined microcomputer, resistors, capacitors and otherelectronic parts on the wiring board, for example.

FIG. 35 is a block diagram showing a first embodiment of a schematicarrangement of the digital still camera 300 including the lens barrel 1having the aforementioned arrangement and actions. As shown in FIG. 35,this digital still camera 300 includes the lens barrel 1, a videorecording/reproducing circuit unit 330 which plays a central role of thecontrol apparatus, a built-in memory 331 including a program memory anda data memory to drive the video recording/reproducing circuit unit 330and other RAM (random-access memory) and ROM (read-only memory) and avideo signal processing unit 332 to process a shot image and the like toprovide a predetermined signal. There are also included the flatdisplay. panel 302 to display shot images and the like, an externalmemory 333 to expand a storage capacity and a lens barrel control unit334 to drive and control the lens barrel 1 and the like.

The video recording/reproducing circuit unit 330 includes an operationcircuit including a microcomputer (CPU), for example, and the like. Thebuilt-in memory 331, the video signal processing unit 332, the lensbarrel control unit 334, the monitor driving unit 334, an amplifier 336and two interfaces (I/Fs) 337 and 338 are connected to this videorecording/reproducing circuit unit 330. The video signal processing unit332 is connected to the CCD 7 attached to the lens barrel 1 through theamplifier 336. A signal processed as a predetermined signal by the videosignal processing unit 332 is inputted to the videorecording/reproducing circuit unit 330.

The flat display panel 302 is connected through the monitor driving unit335 to the video recording/reproducing circuit unit 330. A connector 339is connected to the first interface (I/F) 337 and the external memory333 can be detachably connected to this connector 339. Also, aconnection terminal 340 provided on the camera case 301 is connected tothe second interface (I/F) 338. Then, the lens drive unit 341 to driveand control the lens barrel 1 and a position sensor 342 to detect arotation amount of the lens barrel 1, a movement amount of the lensbarrel 1 to the optical axis direction and the like are connected to thelens barrel control unit 334.

Thus, when an object image is inputted to the lens system of the lensbarrel 1 and focused on the focusing screen of the CCD 7, an imagesignal from the CCD 7 is inputted through the amplifier 336 to the videosignal processing unit 332. A signal processed as a predetermined videosignal by the video signal processing unit 332 is inputted to the videorecording/reproducing circuit unit 330. Accordingly, the signalcorresponding to the object image is outputted from the videorecording/reproducing circuit unit 330 to the monitor drive unit 335 andthe built-in memory 331 or the external memory 333. As a result, animage corresponding to the object image is displayed on the flat displaypanel 302 or the image corresponding to the object image is recorded onthe built-in memory 331 or the external memory 333 as an informationsignal if necessary.

The digital still camera 300 having the above-mentioned arrangement canbe used as follows, for example. FIG. 32 shows the state in which theoptical lens system is closed by closing the opening and closing spring10 b of the lens barrier unit 110 in the lens barrel 1, that is, thenon-shooting state. In this case, the power supply of the digital stillcamera 300 is set to the off-state. Also, FIG. 33 shows the state inwhich the optical lens system is opened by opening the opening andclosing spring 10 b of the lens barrier unit 110, that is, the shootingpossible state. This shooting possible state can be automaticallyexecuted by operating the power supply button 309 to turn on the powersupply. As a result, the digital still camera 300 is changed from thestate shown in FIG. 32 to the state shown in FIG. 33.

In the shooting possible state of the digital still camera 300, when acameraman directs the camera lens to the object and presses the shutterrelease button 310, the cameraman is able to take a picture of theobject and is able to get an image of the object. In that case, when thecameraman operates the optical zoom operation button 317, it is possibleto obtain a wide (wide-angle lens) picture or telephoto (telephoto-lens)picture by continuously changing a focal length in response to theoperation direction without changing an image point.

As set forth above, according to the present invention, in the lensbarrel including the cam ring with the outer peripheral gear train, itis possible to increase the length of the optical axis direction of thecam groove without increasing the whole length of the optical axisdirection of the cam ring. Therefore, since the length of the opticalaxis direction of the cam groove is not changed, it is possible todecrease the whole length of the optical axis direction of the cam ring,accordingly, it is possible to miniaturize the whole of the lens barrel.While the lens is used as the optical element as described above in theabove-described embodiments, the optical element is not limited to theabove-described embodiments and it is needless to say that an opticalfilter, a prism and other optical elements, for example, can be used.

The present invention is not limited to the embodiments that have beendescribed so far with reference to the drawings and it can be variouslymodified without departing from the gist thereof. For example, while thedigital still camera is applied to a camera apparatus in theabove-described embodiments, the present invention is not limitedthereto and the present invention can be applied to a digital videocamera, a personal computer having a built-in camera, a mobile phonehaving a built-in camera and other camera apparatus. Further, while thethree group lens is used as the optical lens as described above, thepresent invention is not limited thereto and it is needless to say thatlenses less than a two group lens or lenses greater than a four grouplens may be used as the optical lens.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A lens barrel cam mechanism including: a linearly movable member for holding an optical element and which can be moved in the optical axis direction of said optical element, said linearly movable member including a cam follower; and a rotary member rotatable relative to said linearly movable member and which can be also moved relatively to said optical axis direction, said rotary member having a cam groove with which said cam follower is slidably engaged formed on its circumferential surface, wherein said rotary member is rotated to guide said cam follower with said cam groove so that said linearly movable member is moved forward and backward in said optical axis direction, comprising: a gear portion provided at least a part of one end of a rotation axis direction of said rotary member, said gear portion being developed at the outside of a radius direction and having teeth on its outer periphery; and a cam groove opening portion provided by opening an end portion of said gear portion side of said cam groove to the end surface of said rotary member, wherein said cam groove opening portion and said gear portion are provided such that they become substantially coincident with each other on the same vertical plane vertical to said optical axis direction.
 2. A lens barrel cam mechanism according to claim 1, wherein said rotary member includes a cylindrical-shaped cylindrical body portion having said cam groove formed thereon, said cylindrical body portion has a plurality of cam grooves formed on its outer peripheral surface at substantially an equal space in the circumferential direction, when at least one of said plurality of cam grooves is continued to said gear portion, said gear portion has a through-hole extended thereto and said through-hole has said cam groove opening portion formed thereon.
 3. A lens barrel cam mechanism according to claim 1, further comprising: a fixed ring for supporting said rotary member such that said rotary member can be moved in said optical axis direction; and a cam groove for guiding said rotary member in the direction parallel to said optical axis direction and wherein said rotary member includes a cam projected portion which is slidably engaged with said cam groove.
 4. A lens barrel cam mechanism according to claim 3, wherein said cam projected portion of said rotary member and said gear portion are provided such that they become substantially coincident with each other on the same vertical plane vertical to said optical axis direction.
 5. A method of manufacturing a rotary member in which a rotary member includes a cylindrical-shaped cylindrical body portion having a plurality of cam grooves formed on its outer peripheral surface at substantially an equal space in the circumferential direction and a gear portion continued to at least a part of one end of axis direction of said cylindrical body portion, said gear portion developed to the outside of a radius direction and having teeth formed on its outer periphery, when at least one of said plurality of cam grooves is continued to said gear portion, said gear portion has a through-hole extended thereto and said through-hole has a cam groove opening portion formed thereon, comprising the step of: providing a split mold to injection-mold said rotary member, wherein said split mold is composed of an upper die and a lower die to form a space portion corresponding to a shape of said rotary member and a plurality of side dies to carry out mold release operations in the direction perpendicular to said upper die and said lower die and said through-hole is formed by a die matching surface of said upper die or said lower die and said side dies. 